Coupler circuit

ABSTRACT

Aspects of this disclosure relate to a coupler circuit configured to receive an output of a radio frequency coupler. The coupler circuit can be arranged in a daisy chain with other coupler circuits. The coupler circuit can include a switch configured to turn on based on a signal level of a direct current component of a coupler signal from another coupler circuit and pass a radio frequency component of the coupler signal when on. The coupler circuit can pass the coupler signal while a module that includes the coupler circuit is otherwise inactive.

CROSS REFERENCE TO PRIORITY APPLICATION

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR § 1.57.This application claims the benefit of priority under 35 U.S.C. § 119(e)of U.S. Provisional Patent Application No. 62/398,705, filed Sep. 23,2016 and titled “COUPLER CIRCUIT,” the disclosure of which is herebyincorporated by reference in its entirety herein.

BACKGROUND Technical Field

Embodiments of this disclosure relate to electronic systems and, inparticular, to radio frequency circuits.

Description of Related Technology

A radio frequency (RF) coupler can extract a portion of power of an RFsignal propagating between ports of the RF coupler. A power detector incommunication with an RF coupler can detect a power level of the RFsignal and provide an output indicative of the power level of the RFsignal.

RF systems can include a plurality of RF couplers and a number of powerdetectors. Such RF systems can include circuitry configured to receivean output of an RF coupler and to provide a coupler signal to a powerdetector. In certain contexts, providing a coupler signal from an RFcoupler to a power detector is becoming more complicated.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

The innovations described in the claims each have several features, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope of the claims, some prominent features ofthis disclosure will now be briefly described.

One aspect of this disclosure is a radio frequency system with couplercircuits arranged in a daisy chain. The radio frequency system includesa first coupler circuit configured to receive a first signal from afirst radio frequency coupler and a second coupler circuit configured toreceive a second signal from a second radio frequency coupler. The firstcoupler circuit and the second coupler circuit are arranged in a daisychain. The second coupler circuit includes a switch configured to turnon based on a signal level of a direct current component of a couplersignal from the first coupler and to pass a radio frequency component ofthe coupler signal when on.

A first packaged module can include the first coupler circuit and asecond packaged module can include the second coupler circuit. Thesecond coupler circuit can pass the coupler signal from the firstcoupler circuit while the second packaged module is otherwise inactive.

The radio frequency system can further include a power detector havingan input coupled to an output of the daisy chain. The power detector canprovide an indication of power of a single carrier of a carrieraggregated signal. A direct current blocking element can be coupledbetween the output of the daisy chain and the input of the powerdetector. The power detector can be included in a transceiver.

The radio frequency system can include a frequency multiplexing circuitconfigured to receive a first output signal from a first signal paththat includes the first radio frequency coupler, to receive a secondoutput signal from a second signal path that includes the second radiofrequency coupler, and to provide a carrier aggregated signal.

The radio frequency system can further include a third coupler circuitarranged in the daisy chain.

The second coupler circuit can include a radio frequency signal path anda direct current signal path, in which the radio frequency signal pathincludes the switch. The direct current signal path can pass the directcurrent component of the coupler signal to the output port when theswitch is on.

Another aspect of this disclosure is a radio frequency system withcoupler circuits arranged in a daisy chain. The radio frequency systemincludes a first module and a second module. The first module includes afirst coupler circuit configured to receive a first signal from a firstradio frequency coupler. The second module includes a second couplercircuit configured to receive a second signal from a second radiofrequency coupler. The first coupler circuit and the second couplercircuit are arranged in a daisy chain. The second coupler circuit isconfigured to pass a coupler signal from the first coupler circuit whilethe second module is otherwise inactive.

The radio frequency system can further include a power detector havingan input coupled to an output of the daisy chain. The power detector canbe configured to provide an indication of power of a single carrier of acarrier aggregated signal. The radio frequency system can furtherinclude a frequency multiplexing circuit configured to receive an outputof the first module and an output of a third module, and to provide acarrier aggregated signal. The radio frequency system can furtherinclude a third coupler circuit arranged in the daisy chain.

Another aspect of this disclosure is a coupler circuit for passing acoupler signal. The coupler circuit includes an input port configured toreceive an input signal having a direct current component and a radiofrequency component, a radio frequency signal path including a switchconfigured to turn on based on the signal level of a direct currentcomponent of the input signal and to pass the radio frequency componentof the input signal to an output port using the switch, and a directcurrent signal path configured to pass the direct current component ofthe input signal to the output port when the switch is on.

The radio frequency signal path can include a direct current blockingelement coupled between the switch and the output port. The directcurrent blocking element can include a capacitor. The radio frequencysignal path can receive an output from a radio frequency coupler at anode between the switch and the direct current blocking element. Theradio frequency signal path can include another direct current blockingelement coupled between the input port and the switch.

The coupler circuit can pass the direct current component and the radiofrequency component to the output port when a module that includes thecoupler circuit is otherwise inactive.

The direct current signal path can include a second switch and a radiofrequency blocking circuit coupled between the second switch and theoutput port. The radio frequency blocking circuit can include an RCfilter. The coupler circuit can include a third switch configured toprovide a direct current signal to a node between the second switch andthe radio frequency blocking circuit when the second switch is off. Thecoupler can further include another switch coupled to a control terminalof the second switch and configured to turn on responsive to the signallevel of the direct current component of the input signal. The couplercircuit can include another radio frequency blocking circuit coupledbetween the second switch and the input port.

Another aspect of this disclosure is a wireless communication devicethat includes a first module, a second module, an antenna, and a powerdetector. The first module includes a first radio frequency coupler andfirst coupler circuit configured to receive a first signal from thefirst radio frequency coupler. The second module includes a second radiofrequency coupler and a second coupler circuit configured to receive asecond signal from the second radio frequency coupler. The first couplercircuit and the second coupler circuit are arranged in a daisy chain.The second coupler circuit includes a switch configured to turn on basedon a signal level of a direct current component of a coupler signal fromthe first coupler circuit and to pass a radio frequency component of thecoupler signal when on. The antenna is configured to transmit a carrieraggregated signal that includes a first carrier and a second carrier.The first carrier is provided by one of the first module or the secondmodule. The power detector has an input coupled to an output of thedaisy chain. The power detector is configured to provide an indicationof power of the first carrier of the carrier aggregated signal.

The second coupler circuit can pass the coupler signal from the firstcoupler circuit while the second module is otherwise inactive.

The second coupler circuit can include a radio frequency signal pathincluding a switch configured to turn on based on a signal level of adirect current component of the coupler signal and to pass a radiofrequency component of the coupler signal to an output port when theswitch is on. The second coupler circuit can include direct currentsignal path configured to pass the direct current component of thecoupler signal to the output port when the switch is on.

The wireless communication device can further include a frequencymultiplexing circuit configured to receive a first output signal from afirst signal path associated with the first coupler circuit, to receivea second output signal from a second signal path associated with thesecond coupler circuit, and to provide the carrier aggregated signal.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the innovations have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment. Thus, theinnovations may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of a coupler circuit according to anembodiment.

FIG. 2 is a schematic diagram of coupler circuits arranged in a daisychain according to an embodiment.

FIG. 3 is a schematic diagram of a coupler circuit according to anembodiment.

FIG. 4 is a schematic diagram of a radio frequency system with couplercircuits arranged in a daisy chain according to an embodiment.

FIG. 5 is a schematic diagram of a radio frequency system with couplercircuits arranged in a daisy chain according to another embodiment.

FIG. 6 is a schematic diagram of a radio frequency system with couplercircuits arranged in a daisy chain according to another embodiment.

FIG. 7A is a schematic diagram of radio frequency system with a couplercircuit according to an embodiment.

FIG. 7B is a schematic diagram of radio frequency system with a couplercircuit according to another embodiment.

FIG. 7C is a schematic diagram of radio frequency system with a couplercircuit according to another embodiment.

FIG. 7D is a schematic diagram of radio frequency system with a couplercircuit according to another embodiment.

FIG. 7E is a schematic diagram of radio frequency system with a couplercircuit according to another embodiment.

FIG. 7F is a schematic diagram of radio frequency system with a couplercircuit according to another embodiment.

FIG. 8 is a block diagram of a packaged module that includes a couplercircuit according to an embodiment.

FIG. 9 is a block diagram of a wireless communication device thatincludes a coupler circuit according to an embodiment.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals canindicate identical or functionally similar elements. It will beunderstood that elements illustrated in the figures are not necessarilydrawn to scale. Moreover, it will be understood that certain embodimentscan include more elements than illustrated in a drawing and/or a subsetof the elements illustrated in a drawing. Further, some embodiments canincorporate any suitable combination of features from two or moredrawings.

It can be desirable to detect power of a power amplifier in an RF frontend. Power can be dynamically adjusted in a closed loop. Such dynamicpower adjustment can be based on a distance from a base station, forexample. With the advent of uplink carrier aggregation for fourthgeneration Long Term Evolution (4G LTE), multiple power detectors can beimplemented in a transceiver to process coupled outputs from variouspower amplifiers. In a 2-uplink carrier aggregation case, 2 powerdetectors can be integrated into the transceiver to process the coupledsignals from two power amplifiers that transmit simultaneously. Tosupport multiple uplink carrier aggregation combinations (e.g., low bandand high band, mid band and high band, etc.), coupler signal flow frompower amplifiers to the transceiver has become more complicated. Usingthe daisy chain techniques discussed herein can enable detection ofpower associated with individual power amplifiers of various uplinkcarrier aggregation combinations.

Techniques discussed herein relate to a coupler signal propagatingthrough a daisy-chain through active and/or inactive modules to a singleoutput. For instance, techniques disclosed herein relate to a couplersignal propagating through coupler circuits arranged in a daisy chain toa single output, in which the coupler circuits include both a firstcoupler circuit on an active module and a second coupler circuit on aninactive module. By enabling the coupler signal to flow through one ormore otherwise inactive modules, power consumption can be reduced andassociated control can be simplified. Such techniques can be implementedwithout otherwise turning on and/or controlling any inactive modulesthat include circuitry that is part of the daisy chain.

Some previous attempts to process coupler signals from carrieraggregation systems involved controlling each of the modules thatinclude a coupler circuit in a daisy chain using a serial bus, such as aMPIP RF Front End Interface (MIPI RFFE). However, these previousattempts increased overall power consumption by turning on inactivemodules to allow a coupler signal to pass through the modules that wouldhave otherwise been inactive. Moreover, such previous attempts involvedadditional complexity to keep track of the inactive modules in the daisychain and turn them on as desired to pass the coupler signal.

Embodiments discussed herein can efficiently pass a coupler signalthrough an inactive module. This can reduce and/or minimize system powerconsumption associated with passing a coupler signal to a powerdetector. Embodiments discussed herein can simplify control of modules,as the coupler circuits discussed herein can pass a received couplersignal in an inactive module without any other control signals beingtoggled and/or provided to the inactive module.

FIG. 1 is a schematic diagram of a coupler circuit 10 according to anembodiment. The coupler circuit 10 can be implemented in each of aplurality of modules to enable a coupler signal to flow through bothactive and inactive modules. The coupler circuits in the plurality ofmodules can be arranged in a daisy chain. The coupler circuit 10includes direct current (DC) blocking capacitors and RC filters toseparate DC and radio frequency (RF) components at an input port CPL_INand combine DC and RF components at an output port CPL_OUT. Additionalcircuitry in the DC path of the coupler circuit 10 can allow the DCsignal component to flow from the input port CPL_IN to output portCPL_OUT only or to add a DC signal component to the output port CPL_OUTas desired.

As shown in FIG. 1, the coupler circuit 10 includes an input portCPL_IN, an output port CPL_OUT, an internal coupler signal portInternal_CPLout, an internal bias port Internal_CPL_Bias_En, an internalcoupler enable port Internal_CPL_En, an external coupler select portExt_CPL_Sel, switches M₁ to M₇, capacitors C₁ to C₄, and resistors R₁ toR₉. The coupler circuit 10 includes an RF path from the input portCPL_IN to the output port CPL_OUT. The coupler circuit 10 also includesa DC path from the input port CPL_IN to the output port CPL_OUT. Thecoupler circuit 10 includes an internal RF path from the internalcoupler signal port Internal_CPLout to the output port CPL_OUT. Thecoupler circuit 10 also includes an internal DC path from the bias portInternal_CPL_Bias_En to the output port CPL_OUT. Any of the switches M1to M7 can be implemented by any suitable switches. For example, theswitches M1 to M7 can be field effect transistors as illustrated. Insome other instances, one or more of the switches M1 to M7 can beimplemented by another type of transistor or a microelectromechanicalsystems (MEMS) switch. Regardless of the technology, when a switch isturned on, it can pass a signal.

The input port CPL_IN can receive a coupler signal from an output portCPL_OUT of another coupler circuit. The output port CPL_OUT can providea coupler signal from the coupler circuit 10 to an input port CPL_IN ofa coupler circuit downstream in a daisy chain. The output port CPL_OUTcan provide a coupler signal from the coupler circuit 10 to a powerdetector. The coupler signal at the output port CPL_OUT can have an RFsignal component superimposed on a DC signal component.

The coupler signal received at the input power CPL_IN can have a DCcomponent and an RF component. The DC component can activate the couplercircuit 10. Accordingly, the coupler circuit 10 can be referred to as adirect current controlled coupler circuit. In the illustrated couplercircuit 10, the DC component of a coupler signal received at the inputport CPL_IN can turn on a switch M1 to pass the RF component of thecoupler signal from the input port CPL_IN to the output port CPL_OUT.The RF component of the coupler signal can be an indication of power ofan RF signal path. For example, the RF component can be a signal from acoupled out port of a radio frequency coupler. Illustrative examples ofRF signal paths and RF couplers configured to provide the RF componentof the coupler signal to the coupler circuit 10 are shown in FIGS. 7A to7F.

Any of coupler circuits herein can receive a signal from any suitableradio frequency coupler including, for example, a directional coupler, abi-directional coupler, a dual-directional coupler, a multi-band coupler(e.g., a dual-band coupler), etc. As an example, a radio frequencycoupler can be a 4 terminal device having a power input port, a poweroutput port, a coupled out port, and an isolated port. The radiofrequency coupler can extract a portion of power of an RF signalpropagating from the power input port to the power output port. Thecoupled out port can provide a portion of the power of an RF signalpropagating from the power input port to the power output port. Atermination impedance can be coupled to the isolated port.

The coupler circuit 10 includes an RF path from the input port CPL_IN tothe output port CPL_OUT. The coupler circuit 10 can process an RFsignal. Accordingly, the coupler circuit 10 can be referred to as an RFcircuit. The RF path includes a first DC blocking capacitor C₁, a switchM₁, and a second DC blocking capacitor C₂. The first DC blockingcapacitor C₁ can block a DC component of a coupler signal received atthe input port CPL_IN. Accordingly, the switch M₁ can receive the RFsignal component of the coupler signal received at the input portCPL_IN. A biasing element, such as resistor R₁, can set a DC voltage ata terminal of the switch M₁. When the switch M₁ is a field effecttransistor, this can set a DC voltage at a drain and/or a source of theswitch M₁. As illustrated, the switch M₁ is an n-type field effecttransistor. The switch M₁ can turn on based on a signal level of the DCcomponent of the coupler signal received at the input port CPL_IN. Forexample, when the DC component is asserted (i.e., at a logic 1 level inthe illustrated coupler circuit 10), the switch M₁ can turn on and passthe RF component of the coupler signal received by way of the firstblocking capacitor C₁. A resistor R₄ can be coupled between the inputport CPL_IN and a control terminal of the switch M₁, which is a gate ofa field effect transistor in FIG. 1.

The second DC blocking capacitor C₂ can block a DC component of aninternal coupler signal provided to the internal coupler signal portInternal_CPLout of the coupler circuit 10. The internal coupler signalcan be provided by a radio frequency coupler of a module that includesthe coupler circuit 10. The internal coupler signal can be generated bythe same module that includes the coupler circuit 10. By contrast, thecoupler signal received at the input port CPL_IN is generated externalto the module that includes the coupler circuit.

The coupler circuit 10 includes a DC path from the input port CPL_IN tothe output port CPL_OUT. The DC path includes a first RC filter, aswitch M₄, and second RF filter. In FIG. 1, the first RF filter includesa resistor R₆ and a capacitor C₃ arranged to filter the RF component ofthe coupler signal received at the input port CPL_IN. For example, thefirst RF filter can be a low pass filter configured to block the RFcomponent of the coupler signal and to pass the DC component of thecoupler signal. Such a low pass filter can have a corner frequency of,for example, about 30 megahertz (MHz). The switch M₄ can pass the DCcomponent of the coupler signal when the coupler circuit 10 is passingthe coupler signal from the input port CPL_IN to the output portCPL_OUT. The switch M₄ can be turned off when the coupler circuit 10 isproviding a DC component of an internal DC signal from the internal biasport Internal_CPL_Bias_En to the output port CPL_OUT. The internal DCsignal is provided by a module that includes the coupler circuit 10. Theswitch M₄ can be a p-type field effect transistor as illustrated.

Another switch M₅ can turn on the switch M₄ and/or maintain the switchM₄ in the on state responsive to a DC component of the coupler signalreceived at the input port CPL_IN being asserted (e.g., corresponding toa logic 1 level). The switch M₅ can enable the switch M₄ to turn offresponsive to a signal at a control terminal of the switch M₅ when theDC component of the coupler signal received at the input port CPL_IN isde-asserted (e.g., corresponding to a logic 0 level). In FIG. 1, thesecond RC filter includes a resistor R₇ and a capacitor C₄ arranged tofilter the RF component of the internal DC signal. The second RC filtercan be a low pass filter configured to block RF components. Such a lowpass filter can have a corner frequency of about 30 MHz, for example.

The coupler circuit 10 includes an internal RF path to the output portCPL_OUT. An internal coupler signal can be provided to an internalcoupler signal port Internal_CPLout. The internal coupler signal portInternal_CPLout is connected to a node between the switch M₁ and thesecond DC blocking capacitor C₂. The internal coupler signal can be anindication of power of a signal in a transmission path, such as anoutput of a power amplifier or a signal downstream in a transmit pathfrom a power amplifier. The internal coupler signal can be provided by acoupled out port of a radio frequency coupler, in which the radiofrequency coupler and the coupler circuit 10 are included on the samemodule. The second DC blocking capacitor C₂ can block a DC component ofthe internal coupler signal.

The coupler circuit 10 includes an internal DC path from the internalbias port Internal_CPL_Bias_En to the output port CPL_OUT. An internalDC signal can be passed by switch M₃ to a node between switch M₄ and thesecond RC filter when the internal DC path is activated. The second RCfilter can filter out any RF components of the internal DC signal. Theswitches M₃ and M₄ can together function as a pass gate in which theswitch M₃ passes the internal DC signal and the switch M₄ passes the DCsignal component of a coupler signal received at the input port CPL_IN.As illustrated, the switches M₃ and M₄ can both be implemented by p-typefield effect transistors. An internal coupler enable signal received atan internal coupler enable port Internal_CPL_En can turn off the switchM₄ so as to enable the internal DC path. When the DC component of thecoupler signal received at input port CPL_IN is at a logic 0 level inthe illustrated coupler circuit 10, the switch M₃ can be on to pass theinternal DC signal and the switches M₄ and M₅ can be off. Accordingly,the illustrated coupler circuit 10 can pass the internal DC signal tothe output port CPL_OUT when the coupler signal received at the inputport CPL_IN has a DC level corresponding to a logic 0 level.

The coupler circuit 10 is also compatible with a MIN based externallycontrolled mode to pass a coupler signal. Accordingly, the illustratedcoupler circuit 10 can operate in a DC biased mode in which a couplersignal is passed in a daisy chain based on a DC component level of acoupler signal or a MIPI based mode. In the MIPI based mode, an externalcoupler control signal can be provided to a switch M₂ to pass an RFcomponent received at the input port CPL_IN. Resistors R₂ and R₃ canassist in achieving desired functionality in the MIPI based mode. Theswitch M₂ can be turned off and turned on responsive to a signalreceived at an external coupler select port Ext_CPL_Sel.

The coupler circuit 10 can also provide isolation and/or electrostaticdischarge (ESD) protection. A shunt switch M₆ can provide isolationand/or ESD protection at the input port CPL_IN. The shunt switch M₆ canbe on when the internal DC and RF paths are providing the DC and RFcomponents at the output port CPL_OUT. A shunt switch M₇ can provide ESDprotection at the output port CPL_OUT. The shunt switches M₆ and M₇ canreceive signals at their control terminals by way of resistors R₈ andR₉, respectively.

Although the coupler circuit 10 may be described with signals havingcertain logic levels (e.g., logic 0 or logic 1), a coupler circuit canbe implemented with one or more signals having a different (e.g.,complementary) logic level. This can involve using transistors havingdifferent conductivity types, etc.

The coupler circuits discussed herein can be implemented in modules. Amodule can include circuitry included within a common package. Such amodule can be referred to as a packaged module. A packaged module caninclude a semiconductor die and one or more passive components on apackaging substrate enclosed within a common package. Some such packagedmodules can be multi-chip modules. The semiconductor die can bemanufactured using any suitable process technology. As one example, thesemiconductor die can be a semiconductor-on-insulator die, such as asilicon-on-insulator die. As another example, the semiconductor die canbe a gallium arsenide die.

FIG. 2 is a schematic diagram of a radio frequency system 20 in whichcoupler circuits 10 a, 10 b, and 10 c are arranged in a daisy chainaccording to an embodiment. Each of the coupler circuits 10 a, 10 b, and10 c can implement the coupler circuit 10 of FIG. 1 in a differentmodule. In particular, the coupler circuit 10 a can be implemented inmodule 1, the coupler circuit 10 b can be implemented in module 2, andthe coupler circuit 10 c can be implemented in module 3. As illustrated,each of the coupler circuits 10 a, 10 b, and 10 c have the same circuittopology. This can provide flexibility in arranging the modules thatinclude these coupler circuits in a daisy chain and/or including one ofmore of the coupler circuits in a different daisy chain arrangement withone or more coupler circuits from one or more other modules. Couplercircuits of different modules can be electrically connected to eachother by way of contacts (e.g., pins, pads, etc.) of the modules. Onlyone of the coupler circuits 10 a, 10 b, and 10 c can be receiving aninternal coupler signal from an RF coupler at a time. A DC blockingelement 22 can be coupled between an output of the daisy chain and atransceiver 24. The DC blocking element 22 can be a DC blockingcapacitor arranged to block a DC component of the output of the daisychain. A power detector of the transceiver 24 can receive the output ofthe daisy chain with the DC component stripped and provide an indicationof power of a signal associated with a signal path of an active module.As shown in FIG. 2, modules 1 and 3 are inactive and module 2 is active.Accordingly, the power detector can provide an indication of power of asignal path of module 2 in a state corresponding to FIG. 2.

In FIG. 2, module 1 is inactive and the coupler circuit 10 a can beinactive. The coupler circuit 10 a of module 1 can provide a couplersignal to the coupler circuit 10 b of module 2 that has a DC componentcorresponding to a signal level indicating that the coupler circuit 10 ais not providing an indication of power from an RF coupler of module 1.For example, as illustrated, the coupler signal provided by module 1 tomodule 2 has a DC component with a logic 0 level.

In FIG. 2, module 2 is active. The coupler circuit 10 b of module 2 canreceive an internal coupler signal from an RF coupler. The couplercircuit 10 b can also receive an internal DC signal. The internalcoupler signal and the internal DC signal can be combined at the outputport CPL_OUT of the coupler circuit 10 b by way of an internal RF pathand an internal DC path, respectively, of the coupler circuit 10 b. Thecoupler circuit 10 b can provide a coupler signal that has a DCcomponent corresponding to a signal level indicating that the coupler 10b is providing an indication of power from an RF coupler of module 2.The coupler signal provided by the coupler signal 10 b can also have anRF component corresponding to the indication of power from the RFcoupler of module 2.

The coupler signal provided by the coupler circuit 10 b to the couplercircuit 10 c can activate the coupler circuit 10 c. The coupler circuit10 c can be activated while module 3 is otherwise inactive. The DCcomponent of the coupler signal from the coupler circuit 10 b canactivate an RF path of the coupler circuit 10 c. As shown in FIG. 2, theswitch M₁ of the RF path of the coupler circuit 10 c can be turned onresponsive to the DC component of the coupler signal provided by thecoupler circuit 10 b being at a logic 1 level. As also shown in FIG. 2,the switch M₄ of the DC path can be maintained on and/or turned onresponsive to the DC component of the coupler signal provided by thecoupler circuit 10 b being at a logic 1 level. In the coupler circuit 10c, the switch M₅ can be turned on responsive to the coupler signalprovided by the coupler circuit 10 b being at a logic 1 level, which canconsequently maintain the switch M₄ on and/or turn on the switch M₄.With the RF path and the DC path being active, the coupler signal fromthe coupler circuit 10 b can be passed through the coupler circuit 10 c.The coupler circuit can propagate from the output port CPL_OUT of thecoupler circuit 10C to a power detector of the transceiver 24 by way ofthe DC blocking element 22.

While FIG. 2 illustrates three coupler circuits 10 a, 10 b, and 10 cthat include the same circuit topology, one or more of the couplercircuits in a daisy chain of coupler circuits can include a differentcircuit topology than one or more other circuits of the daisy chain. Forexample, a coupler circuit though which all other coupler circuits ofthe daisy chain are connected to a power detector can be implementedwithout a DC path in certain instances. In such instances, a DC blockingelement can be omitted between an output of the daisy chain and a powerdetector. As another example, a coupler circuit that does not receive aninput from another coupler circuit of the daisy chain can omit circuitelements for processing a coupler signal provided by another couplercircuit.

FIG. 3 is a schematic diagram of a coupler circuit 30 according to anembodiment. A plurality of coupler circuits 30 can be arranged in adaisy chain in accordance with any of the principles and advantagesdiscussed herein. The coupler circuit 30 includes some features of thecoupler circuit 10 of FIG. 1. The coupler circuit 30 can implementsimilar functionality as the coupler circuit 10.

The coupler circuit 30 includes an RF path from an input port CPL_IN toan output port CPL_OUT and a DC path from the input port CPL_IN to theoutput port CPL_OUT. The RF path can pass an RF component of a couplersignal received at the input port CPL_IN. The RF path includes a firstDC blocking element 32, a switch M₁, and a second DC blocking element34. The DC blocking element 32 can be any suitable circuit element(s),such as a capacitor, to block a DC component of the coupler signalreceived at the input port CPL_IN. The switch M₁ can turn on based on asignal level of the DC component of the coupler signal received at theinput port CPL_IN.

The DC path of the coupler circuit 30 can pass the DC component of thecoupler signal received at the input port CPL_IN. The DC path includes afirst RF blocking element 36, a switch M₄, and a second RF blockingelement 38. The RF blocking element 36 can be any suitable circuitelement(s), such as a low pass filter, to block an RF component of thecoupler signal received at the input port CPL_IN. The switch M₄ can beon when a module that includes the coupler circuit 30 is inactive. Theswitch M₄ can be on when an internal coupler signal port Internal_CPLoutis not providing a coupled out signal from an RF coupler indicative ofpower in an RF signal path. The switch M₄ can be controlled based on asignal received at the internal coupler enable port Internal_CPL_Enindicating whether the RF coupler is providing a coupled out signalindicative of RF power.

In the coupler circuit 30, an internal coupler signal can be received atthe internal coupler signal port Internal_CPLout and provided to a nodebetween the switch M₁ and the DC blocking element 34. An internal DCsignal can be received at an internal bias port Internal_CPL_Bias_En andprovided by way of the switch M₃ to a node between the switch M₄ and theRF blocking element 38.

FIG. 4 is a schematic diagram of a radio frequency system 40 withcoupler circuits arranged in a daisy chain according to an embodiment.The RF system 40 can transmit a carrier aggregated signal. Accordingly,the RF system 40 can be referred to as a carrier aggregation system.

As illustrated, the RF system 40 includes a first module 41A, a secondmodule 41B, a third module 42, a transceiver 43, an RF switch 44, adiplexer 45, and an antenna 46. The modules 41A, 41B, and 42 eachinclude an RF signal path 47A, 47B, and 47C, respectively. The modules41A and 41B each include a coupler circuit 48A and 48B, respectively.The coupler circuits 48A and 48B can be implemented in accordance withany suitable principles and advantages discussed herein. For example,the coupler circuit 48A can be implemented by the coupler circuit 10 ofFIG. 1 or the coupler circuit 30 of FIG. 3. The modules 41A, 41B, 42 caneach provide an RF signal as an output. The RF switch 44 can selectivelyelectrically couple an output of the first module 41A or an output ofthe second module 41B to the diplexer 45. The diplexer 45 can frequencymultiplex an output signal from the RF switch 44 with the output signalfrom the third module 42 to generate a carrier aggregated signal. Thecarrier aggregated signal can be transmitted by the antenna 46.

In the RF system 40, the first module 41A can be a low band module, thesecond module 41B can be a mid band module, and the third module 42 canbe a high band module. A carrier aggregated signal transmitted by theantenna 46 can include either (1) a low band carrier and a high bandcarrier, or (2) a mid band carrier and a high band carrier. Accordingly,only two of the modules 41A, 41B, and 42 can be active at the same time.In this example, only one of the first module 41A or the second module41B can be active at time. Since the first module 41A and the secondmodule 41B are not transmitting at the same time, one of these modulescan be active and the other module can be inactive.

The coupler circuits 48A and 48B of the first module 41A and the secondmodule 41B, respectively, are arranged in a daisy chain. Only one of thecoupler circuits 48A or 48B can receive an internal coupler signal thatis indicative of power of a carrier being transmitted by the antenna 46from a respective RF signal path 47A or 47B. The coupler signal can beprovided to a power detector 49B of the transceiver 43 to detect powerassociated with the carrier. A DC blocking capacitor 50 can be coupledbetween the daisy chain of coupler circuits and the power detector 49Bto block a DC signal component.

As illustrated, the transceiver 43 includes a first power detector 49Aand a second power detector 49B. The first power detector 49A can detecta power associated with a carrier of the third module 42. The secondpower detector 49B can detect a power of a carrier associated witheither the first module 41A or the second module 41B depending on whichof these modules is active. The transceiver 43 can process outputs ofthe power detectors and send feedback signals to respective modules 41A,41B, and 42 to adjust power based on the detected power levels.

FIG. 5 is a schematic diagram of a radio frequency system 52 withcoupler circuits arranged in a daisy chain according to anotherembodiment. The radio frequency system 52 includes a first group ofmodules 41A1 to 41N1 having coupler circuits 48A1 to 48N1, respectively,arranged in a daisy chain and a second group of modules 41A2 to 41M2having coupler circuits 48A2 to 48M2, arranged in another daisy chain.The coupler circuits of the radio frequency system 52 can be implementedin accordance with any suitable principles and advantages discussedherein. For example, any of the illustrated coupler circuits can beimplemented by the coupler circuit 10 of FIG. 1 or the coupler circuit30 of FIG. 3. Any suitable number of coupler circuits can be arranged ina daisy chain in accordance with any of the principles and advantagesdiscussed herein. Each daisy chain can include coupler circuits in whichonly one coupler circuit is arranged to receive an internal couplersignal at a time and the remaining coupler circuits are either inactiveor arranged to pass the coupler signal from the one coupler signal thatis receiving the internal coupler signal. Any suitable number of daisychained coupler circuits can be implemented in a radio frequency system.In the RF system 52, the transceiver 43 includes power detectors 49A and49B each arranged to receive an output of a different daisy chain. DCblocking capacitors 50A and 50B can be coupled between outputs ofrespective daisy chains and respective detectors 49A and 49B.

FIG. 6 is a schematic diagram of a radio frequency system 60 withcoupler circuits arranged in a daisy chain according to anotherembodiment. The RF system 60 illustrates that a module 62 can includemultiple coupler circuits 48A1 and 48A2 included in different daisychains of coupler circuits. The RF signal path 47A of module 62 caninclude a first portion that is active when the module 41C is active anda second portion that is active when the module 41B is active. The firstportion of the RF signal path 47A can include a first RF coupler havinga coupled out port configured to provide an internal coupler signal to afirst coupler circuit 48A1. The second portion of the RF signal path 47Acan include a second RF coupler having a coupled out port configured toprovide an internal coupler signal to a second coupler circuit 48A2.Accordingly, each of the daisy chains illustrated in FIG. 6 can have nomore than one coupler circuit arranged to receive an internal couplersignal at a time.

FIGS. 7A to 7F are schematic diagrams of radio frequency systems with acoupler circuit according to various embodiments. Different modules thatinclude coupler circuits arranged in a daisy chain can include RF signalpaths that include one or more features of the RF systems of FIGS. 7A to7F. The RF signal paths of different modules can include different RFsignal paths and/or similar RF signal paths. The RF systems of FIGS. 7Ato 7F include illustrative examples of RF signal paths that can beimplemented in any suitable RF signal path of FIGS. 4 to 6. The RFsystems of FIGS. 7A to 7F illustrate example systems in which a couplercircuit 48 can be implemented. The coupler circuit 48 can be implementedin accordance with any suitable principles and advantages of any of thecoupler circuits discussed herein, such as the coupler circuit 10 ofFIG. 1 and/or the coupler circuit 30 of FIG. 3. Moreover, any suitablecombination of features of the illustrative RF systems of FIGS. 7A to 7Fcan be implemented with each other. In each of the illustrative RFsystems of FIGS. 7A to 7F, an indication of power associated with anamplified RF signal provided by a power amplifier in a transit path canbe provide to a coupler circuit.

FIG. 7A is a schematic diagram of an RF system 70 that includes a poweramplifier 72 configured to amplify an RF signal and an RF coupler 74coupled to an output of the power amplifier 72. The illustrated RFcoupler 74 can be referred to as a directional coupler. The RF coupler74 has a termination impedance 76 (e.g., a termination resistor) coupledto a terminate port. The RF coupler 74 is arranged to provide anindication of power of an amplified RF signal provided by the poweramplifier 72 at a coupled out port. The coupler circuit 48 is arrangedto receive the indication of power of the amplified RF signal as aninternal coupler signal. The internal coupler signal can be provided toan internal RF path of the coupler circuit 48. For instance, theinternal coupler signal can be provided to a port corresponding to theinternal coupler signal port Internal_CPLout of the coupler circuit 10of FIG. 1.

FIG. 7B is a schematic diagram of an RF system 80 that includes an RFcoupler 74 coupled in a signal path between a power amplifier 72 and anRF switch 82. The illustrated RF switch 82 is a multi-throw switch, suchas a band select switch. As illustrated, the RF coupler 74 is coupledbetween an output of the power amplifier 72 and a common port of the RFswitch 74.

FIG. 7C is a schematic diagram of an RF system 85 that illustrates aclosed loop that can adjust power of an amplified RF signal provided bythe power amplifier 72. The closed loop can include coupler circuitsarranged in a daisy chain and a power detector 49 arranged to receive anoutput of the daisy chain. An input to the power amplifier 72 can beadjusted based on a detected power level detected by the power detector49. A signal provided to the power amplifier 72 by the transceiver 86can be adjusted based on an output of the power detector 49.

FIG. 7D is a schematic diagram of an RF system 90 that includes an RFcoupler 74 coupled in a signal path between a power amplifier 72 and atransmit/receive switch 92. The transmit/receive switch 92 canselectively electrically couple the power amplifier 72 or a low noiseamplifier 94 to a common port of the transmit/receive switch 92.

FIG. 7E is a schematic diagram of an RF system 100 that includes RFswitches 102 and 106 and duplexers 104 coupled between a power amplifier72 and an RF coupler 74. The various paths between an output of thepower amplifier 72 and a common port of the RF switch 106 that isconnected to the RF coupler 74 can include filtering and/or otherprocessing that is tailored for amplifying particular RF signals.

FIG. 7F is a schematic diagram of an RF system 110 that includes afilter 112 and an RF switch 114 coupled in s signal path between thepower amplifier 72 and the RF coupler 74.

FIG. 8 is a block diagram of a packaged module 140 that includes acoupler circuit according to an embodiment. The illustrated packagedmodule 140 includes a packaging substrate 142, an RF circuit 146, an RFcoupler 74, and a coupler circuit 48. The packaging substrate 142 can bea laminate substrate, for example. The RF circuit 146, the RF coupler74, and the coupler circuit 48 can be disposed on the packagingsubstrate 142. The RF circuit 146 can be any suitable circuit configuredto provide an RF signal, such as a circuit that includes a poweramplifier. The coupler circuit 48 of the module 140 can be arranged in adaisy chain with one or more other coupler circuits in accordance withany of the principles and advantages discussed herein.

FIG. 9 is a block diagram of a wireless communication device 150 thatincludes coupler circuits arranged in a daisy chain according to anembodiment. The wireless communication device 150 can be any suitablewireless communication device. For instance, a wireless communicationdevice 150 can be a mobile phone, such as a smart phone. As illustrated,the wireless communication device 150 includes an antenna 151, an RFfront end 152, a transceiver 153, a processor 154, and a memory 155. Theantenna 151 can transmit RF signals provided by the RF front end 152.The antenna 151 can transmit carrier aggregated signals provided by theRF front end 152. The antenna 151 can provide received RF signals to theRF front end 152 for processing.

The RF front end 152 can include one or more power amplifiers, one ormore low noise amplifiers, RF switches, receive filters, transmitfilters, duplex filters, or any combination thereof. The RF front end152 can transmit and receive RF signals associated with any suitablecommunication standards. For instance, the RF front end 152 can providea carrier aggregated signal to the antenna 151. RF signal pathsdiscussed herein can be implemented in the RF front end 152. The RFfront end 152 can include coupler circuits arranged in a daisy chain.

The RF transceiver 153 can provide RF signals to the RF front end 152for amplification and/or other processing. The RF transceiver 153 canalso process an RF signal provided by a low noise amplifier of the RFfront end 152. The RF transceiver 153 can include one or more powerdetectors arranged to receive an output of a daisy chain of couplercircuits. The RF transceiver 153 can include one or more power detectorsarranged to receive an output of a daisy chain of coupler circuits. TheRF transceiver 153 can provide one or more signals to a transmit path toadjust power of a carrier based on an output of a power detectorarranged to receive an output of a daisy chain of coupler circuits.

The RF transceiver 153 is in communication with the processor 154. Theprocessor 154 can be a baseband processor. The processor 154 can provideany suitable base band processing functions for the wirelesscommunication device 150. The memory 155 can be accessed by theprocessor 154. The memory 155 can store any suitable data for thewireless communication device 150.

Any of the principles and advantages discussed herein can be applied toother systems, not just to the systems described above. The elements andoperations of the various embodiments described above can be combined toprovide further embodiments. Some of the embodiments described abovehave provided examples in connection with power amplifiers and/orwireless communications devices. However, the principles and advantagesof the embodiments can be used in connection with any other systems,apparatus, or methods that benefit could from any of the teachingsherein. For instance, any of the principles and advantages discussedherein can be implemented in connection with detecting power from one ofa plurality of different signal paths of which only one is active at atime. Any of the principles and advantages discussed herein can beimplemented in association with RF circuits configured to processsignals in a range from about 30 kilohertz (kHz) to 300 gigahertz (GHz),such as in a range from about 450 MHz to 6 GHz.

Aspects of this disclosure can be implemented in various electronicdevices. Examples of the electronic devices can include, but are notlimited to, consumer electronic products, parts of the consumerelectronic products such as semiconductor die and/or packaged radiofrequency modules, electronic test equipment, uplink wirelesscommunication devices, personal area network communication devices, etc.Examples of the consumer electronic products can include, but are notlimited to, a mobile phone such as a smart phone, a wearable computingdevice such as a smart watch or an ear piece, a telephone, a television,a computer monitor, a computer, a router, a modem, a hand-held computer,a laptop computer, a tablet computer, a personal digital assistant(PDA), a microwave, a refrigerator, a vehicular electronics system suchas an automotive electronics system, a stereo system, a DVD player, a CDplayer, a digital music player such as an MP3 player, a radio, acamcorder, a camera such as a digital camera, a portable memory chip, awasher, a dryer, a washer/dryer, peripheral device, a clock, etc.Further, the electronic devices can include unfinished products.

Unless the context requires otherwise, throughout the description andthe claims, the words “comprise,” “comprising,” “include,” “including,”and the like are to generally be construed in an inclusive sense, asopposed to an exclusive or exhaustive sense; that is to say, in thesense of “including, but not limited to.” The word “coupled,” asgenerally used herein, refers to two or more elements that may be eitherdirectly coupled to each other, or coupled by way of one or moreintermediate elements. Likewise, the word “connected,” as generally usedherein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements.Additionally, the words “herein,” “above,” “below,” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Wherethe context permits, words in the above Detailed Description of CertainEmbodiments using the singular or plural may also include the plural orsingular, respectively. The word “or” in reference to a list of two ormore items, is generally intended to encompass all of the followinginterpretations of the word: any of the items in the list, all of theitems in the list, and any combination of the items in the list.

Moreover, conditional language used herein, such as, among others,“can,” “could,” “might,” “may,” “e.g.,” “for example,” “such as” and thelike, unless specifically stated otherwise or otherwise understoodwithin the context as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding whether thesefeatures, elements and/or states are included or are to be performed inany particular embodiment.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel methods, apparatus, andsystems described herein may be embodied in a variety of other forms.Furthermore, various omissions, substitutions and changes in the form ofthe methods, apparatus, and systems described herein may be made withoutdeparting from the spirit of the disclosure. For example, circuit blocksdescribed herein may be deleted, moved, added, subdivided, combined,and/or modified. Each of these circuit blocks may be implemented in avariety of different ways. The accompanying claims and their equivalentsare intended to cover any such forms or modifications as would fallwithin the scope and spirit of the disclosure.

What is claimed is:
 1. A radio frequency system with coupler circuitsarranged in a daisy chain, the radio frequency system comprising: afirst coupler circuit configured to receive a first signal from a firstradio frequency coupler; and a second coupler circuit configured toreceive a second signal from a second radio frequency coupler, the firstcoupler circuit and the second coupler circuit arranged in a daisychain, and the second coupler circuit including a switch configured toturn on based on a signal level of a direct current component of acoupler signal from the first coupler and to pass a radio frequencycomponent of the coupler signal when on.
 2. The radio frequency systemof claim 1 wherein a first packaged module includes the first couplercircuit and a second packaged module includes the second couplercircuit.
 3. The radio frequency system of claim 2 wherein the secondcoupler circuit is configured to pass the coupler signal while thesecond packaged module is otherwise inactive.
 4. The radio frequencysystem of claim 1 further comprising a power detector having an inputcoupled to an output of the daisy chain, the power detector beingconfigured to provide an indication of power of a single carrier of acarrier aggregated signal.
 5. The radio frequency system of claim 1further comprising a frequency multiplexing circuit configured toreceive a first output signal from a first signal path that includes thefirst radio frequency coupler, to receive a second output signal from asecond signal path that includes the second radio frequency coupler, andto provide a carrier aggregated signal.
 6. The radio frequency system ofclaim 1 further comprising a third coupler circuit arranged in the daisychain.
 7. The radio frequency system of claim 1 wherein the secondcoupler circuit includes a radio frequency signal path and a directcurrent signal path, and the radio frequency signal path includes theswitch.
 8. The radio frequency system of claim 7 wherein the directcurrent signal path is configured to pass the direct current componentof the coupler signal to the output port when the switch is on.
 9. Acoupler circuit for passing a coupler signal, the coupler circuitcomprising: an input port configured to receive an input signal having adirect current component and a radio frequency component; a radiofrequency signal path including a switch configured to turn on based ona signal level of the direct current component of the input signal andto pass the radio frequency component of the input signal to an outputport using the switch; and a direct current signal path configured topass the direct current component of the input signal to the output portwhen the switch is on.
 10. The coupler circuit of claim 9 wherein theradio frequency signal path includes a direct current blocking elementcoupled between the switch and the output port.
 11. The coupler circuitof claim 10 wherein the radio frequency signal path is configured toreceive an output from a radio frequency coupler at a node between theswitch and the direct current blocking element.
 12. The coupler circuitof claim 10 wherein the radio frequency signal path includes anotherdirect current blocking element coupled between the input port and theswitch.
 13. The coupler circuit of claim 9 wherein the coupler circuitis configured to pass the direct current component and the radiofrequency component to the output port when a module that includes thecoupler circuit is otherwise inactive.
 14. The coupler circuit of claim9 wherein the direct current signal path includes a second switch and aradio frequency blocking circuit coupled between the second switch andthe output port.
 15. The coupler circuit of claim 14 further comprisinga third switch configured to provide a direct current signal to a nodebetween the second switch and the radio frequency blocking circuit whenthe second switch is off.
 16. The coupler circuit of claim 14 furthercomprising another switch coupled to a control terminal of the secondswitch and configured to turn on responsive to the signal level of thedirect current component of the input signal.
 17. A wirelesscommunication device comprising: a first module including a first radiofrequency coupler and first coupler circuit configured to receive afirst signal from the first radio frequency coupler; a second moduleincluding a second radio frequency coupler and a second coupler circuitconfigured to receive a second signal from the second radio frequencycoupler, the first coupler circuit and the second coupler circuitarranged in a daisy chain, and the second coupler circuit including aswitch configured to turn on based on a signal level of a direct currentcomponent of a coupler signal from the first coupler circuit and to passa radio frequency component of the coupler signal when on; an antennaconfigured to transmit a carrier aggregated signal that includes a firstcarrier and a second carrier, the first carrier being provided by one ofthe first module or the second module; and a power detector having aninput coupled to an output of the daisy chain, the power detectorconfigured to provide an indication of power of the first carrier of thecarrier aggregated signal.
 18. The wireless communication device ofclaim 17 wherein the second coupler circuit is configured to pass thecoupler signal from the first coupler circuit while the second module isotherwise inactive.
 19. The wireless communication device of claim 17wherein the second coupler circuit includes a radio frequency signalpath including a switch configured to turn on based on a signal level ofa direct current component of the coupler signal and to pass a radiofrequency component of the coupler signal to an output port when theswitch is on, and the second coupler circuit includes direct currentsignal path is configured to pass the direct current component of thecoupler signal to the output port when the switch is on.
 20. Thewireless communication device of claim 17 further comprising a frequencymultiplexing circuit configured to receive a first output signal from afirst signal path associated with the first coupler circuit, to receivea second output signal from a second signal path associated with thesecond coupler circuit, and to provide the carrier aggregated signal.